Castle origins
Having divorced his first wife, Catherine of Aragon, and married his second wife, Anne Boleyn, in 1533 the threat of war with Europe loomed large for Henry VIII.
He had broken from the Catholic Church to establish his own Church of England, with himself as Supreme Head, to enable his divorce. His first wife, Catherine, was also the maternal aunt of Charles V, the Holy Roman Emperor.
By the end of the decade, Henry had created a ‘device’ (an instruction) to build new artillery fortifications around the English south coast and Thames in response to the risk of invasion from Europe.
Building the castle
The first phase of building work took place between 1539 and 1543, and included construction of Deal, Sandown and Walmer castles in Kent plus a network of Thames blockhouses at Tilbury, Milton and Gravesend.
A second phase of building started in 1544, as tensions with France increased because of England’s siege at Boulogne that same year. Another ‘device’ was issued, and work began on constructing Southsea Castle to protect the Solent and Portsea Island from invasion.
The castle’s strategic location at the entrance to Portsmouth Harbour made it an ideal site for monitoring and controlling maritime traffic. Its stone walls and gun emplacements were designed to deter enemy ships and protect the valuable harbour. The castle’s enduring architectural elements are a testament to the engineering prowess of the time.
The Battle of the Solent
It was only one year later, in 1545, that Southsea Castle saw combat (of sorts) for the first time. In July, a large French invasion fleet arrived off the coast of the Isle of Wight. Other than a short skirmish at sea that saw the loss of the Mary Rose, most of the fighting took place on the Isle of Wight. Southsea Castle didn’t take part in the fighting, but it provided a strategic vantage point for Henry and his land army to observe the battle, and unfortunately watch the Mary Rose as it sank to the Solent seabed during the battle.